For the linear displacement of articles, spindle drives may be used, in which the spindle nut is driven in order to displace the threaded spindle linearly along its axis. In order to achieve a direct conversion of spindle nut rotation into a longitudinal displacement of the threaded spindle, it is necessary to ensure that the threaded spindle does not corotate with the spindle nut. For this purpose, the threaded spindle is usually arranged fixedly in terms of rotation on a reference body which, furthermore, is configured such that it does not impede the rotation of the spindle nut. The reference body may be formed by any desired body, for example by a housing or a frame or else simply by the article to be displaced.
A rotationally fixed arrangement of the threaded spindle on the reference body can be achieved by means of a form fit of the threaded spindle with the reference body, in which, for example, a pin-shaped or wing- or fin-shaped element engages into a longitudinally running groove such that said element can be displaced along the groove, but not transversely with respect to the groove. In order to ensure unimpeded longitudinal displacement of the threaded spindle, the longitudinal direction of the groove is oriented or arranged parallel to the axis of the threaded spindle. Parallel arrangement is also understood in this context to mean the coincidence of the longitudinal direction of the groove with the axis of the threaded spindle. The groove and the element engaging therein together form a longitudinal guide.
The fit between the groove and the element engaging therein must be selected with a view to low conversion losses, such that as little friction as possible occurs. This usually leads to a play which may generate noise when the spindle drive is being used. Furthermore, for reasons of cost, groove geometries which can easily be shaped are mostly selected. Often, for shaping purposes, a mold removal slope is necessary, which leads to a variation in the groove width in the groove longitudinal direction. The play necessitated as a result usually causes an appreciable amount of noise to be generated.